Patterning of Chemical Gradients with Submicrometer Resolution Using Edge‐Spreading Lithography

Edge-spreading lithography is used to assemble mercaptohexadecanoic acid (MHA) and octadecanethiol (ODT) molecules into gradient monolayer ring patterns on a Au substrate. Co-diffusion of both thiols over the surface of immobilized silica beads introduces a partial separation of the two species. Self-assembled monolayers (SAMs) with a gradient structure emerge from the edges of each bead on the Au substrate, as revealed by lateral force microscopy and the template-assisted assembly of nanoparticles (see picture).